# A student measures the time for a pendulum to complete one full swing. She repeats the measurement five times and gets the following results: 1.4 s, 1.5 s, 1.4 s, 1.9 s, 1.4 s. Describe how the student should identify and deal with any anomalous result, and explain how repeating measurements improves the reliability of the final value.

> AQA A-Level Physics (7408) — 3.1.2 Limitations of Physical Measurements · Describe · 5 marks

> A student measures the time for a pendulum to complete one full swing. She repeats the measurement five times and gets the following results: 1.4 s, 1.5 s, 1.4 s, 1.9 s, 1.4 s.

## Mark scheme (5 marks)

1. Identifies 1.9 s as the anomalous result / outlier
2. States that the anomalous result should be excluded / not included when calculating the mean
3. States that the mean (average) of the remaining results should be calculated
4. Explains that repeating measurements reduces the effect of random error
5. Explains that calculating a mean from repeated results gives a more reliable / accurate value

## Key terms

- [anomalous result](https://www.gradenine.co.uk/glossary/anomalous-result)
- [reliability](https://www.gradenine.co.uk/glossary/reliability)

## Related

- [Revision notes for AQA A-Level Physics (7408)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-measures-the-time-for-b8740de3) · Published by Druglandscape Ltd.